1. Field of the Invention
The present invention relates to a vehicular air conditioning apparatus mounted in a vehicle for blowing air into a vehicle compartment that has been adjusted in temperature by a cooling means and a heating means, for thereby performing temperature adjustment of the vehicle compartment.
2. Description of the Related Art
In a vehicular air conditioning apparatus that is mounted in a vehicle, internal and external air is drawn into a casing by a blower, and after cooled air, which has been cooled by an evaporator that forms a cooling means, and heated air, which has been heated by a heater core that forms a heating means, are mixed together in the casing at a predetermined mixing ratio, the mixed air is blown out from a defroster blow-out port, a face blow-out port, or a foot blow-out port, whereby adjustment of temperature and humidity in the vehicle compartment is carried out.
With this type of vehicular air conditioning apparatus, for example, it is known to provide a first blower for the purpose of taking in air from the vehicle compartment into the casing, and a second blower for the purpose of taking in external air outside of the vehicle compartment into the casing. In such a vehicular air conditioning apparatus, air that is introduced from an internal air introduction port by rotation of the first blower is heated by a first heat exchanger and then is blown into the vehicle compartment through a first air passage from the face blow-out port or the foot blow-out port. In addition, air that is introduced from an external air introduction port by rotation of the second blower is heated by a second heat exchanger and then is blown into the vehicle compartment through a second air passage from the defroster blow-out port. More specifically, a switching operation is performed such that when air is blown out from the face blow-out port or the foot blow-out port, the first blower is driven and air from the interior of the vehicle is introduced, whereas when air is blown out from the defroster blow-out port, the second blower is rotated and external air is introduced.
Further, in another vehicular air conditioning device having first and second blowers for introducing air, the first blower is arranged facing toward an external air introducing port of a duct, and the second blower is arranged facing toward an interior air introducing port. Additionally, the first blower includes a switching means, which is capable of switching the air that is introduced to the duct by the first blower between interior air and exterior air.
In addition, the air that is introduced to the duct by the first blower is switched between interior air and exterior air by the switching means, and after the air has been adjusted in temperature by a heating means and a cooling means so as to provide a desired temperature together with the air introduced to the duct by the second blower, the air is blown into a desired region in the vehicle compartment through a face blow-out port, a foot blow-out port, or a defroster blow-out port. (See, for example, Japanese Laid-Open Patent Publication No. 05-178068, Japanese Laid-Open Patent Publication No. 06-040236, and Japanese Laid-Open Patent Publication No. 06-191257.)
However, although reducing energy for heating operation the above-mentioned vehicular air conditioning apparatus does not reduce power consumed by the blowers. In other words, two blowers are driven independently based on the required amounts of the internal air to be circulated and the external air to be introduced. That is, the above-mentioned vehicular air conditioning apparatus is not configured to minimize the total power consumption of the two blowers, in view of the totally required amount of the air that is the sum of the air flow rate of one blower and the air flow rate of the other blower.